v3.26.1
Stock-Based Compensation (Tables)
 3 Months Ended
Mar. 31, 2026
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Schedule of Share-Based Payment Award, Stock Options, Valuation Assumptions
The weighted average assumptions used in the Black-Scholes option pricing model for options granted in three months ended March 31, 2026 and 2025 are as follows:
Stock Option Award AssumptionsMarch 31, 2026March 31, 2025
Expected dividend yield—%—%
Expected life6.50 years6.25 years
Risk-free interest rate5.20%4.22%
Expected volatility49.49%42.33%
Tecogen  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Schedule of Stock Option Activity
Stock option activity for the three months ended March 31, 2026 was as follows: 

Common Stock OptionsNumber of
Options		Exercise
Price
Per
Share		Weighted Average Exercise PriceWeighted
Average
Remaining
Life		Aggregate
Intrinsic
Value
Outstanding, December 31, 20252,347,044 $0.71 —$8.61$1.90 6.29 years$7,961,973 
Granted
50,000 $2.36 $2.36 
Exercised
(58,750)$0.88 —$1.20$0.93 $95,900 
Canceled and forfeited
(65,500)$0.71 —$3.93$0.95 
Outstanding, March 31 20262,272,794 $0.71 —$8.61$1.97 6.10 years$2,933,445 
Exercisable, March 31, 20261,400,458 $1.26 $1,980,445 
Vested and expected to vest, March 31, 20262,141,944 $1.90  $2,790,495